I love the use of Bashō haikus in this movie. Also... best Ghibli grandma, hands down. This and Summer Wars (not Ghibli, but some similar family humor) seem to be fairly faithful to Japanese middle class family dynamics, at least from what I've seen in a couple of the nuclear families that I've become a part of in the US.

I also enjoyed that stark moment when the Dad confronts the biker gang and the art style shifts into something a bit more realistic, then gets back into caricature while Grandma defuses the situation. And again Bashō when it's over:

"How cruel
A grasshopper trapped
Under a warrior's helmet"

while Dad sits on a swing set with his neighborhood watch/fire drill helmet on the ground, sadly fantasizing about kicking ass as a superhero. Just perfect.